GNUR156 exam III

right

what side of the heart supplies the pulmonary circuit?

left

what side of the heart supplies the systemic circuit?

coronary arteries

what supplies heart capillaries?

pressure difference

what drives blood flow?

high to low

what is the direction of blood flow in terms of pressure?

passively

based on pressure gradient, do valves open passively or actively?

SA node, AV node

list the two pacemaker cells of the myocardium

internodal pathways, bundle of his, purkinje fibers

list the conduction fibers of the myocardium

pacemaker, action

name the potentials that Ca causes when it enders SA node cells

K exiting

repolarization of the cell membrane at the SA node is caused by

potential size, potential synchronicity

what two things does distance and amplitude of EKG spread depend on?

atrial depolarization

the P wave represents

ventricular depolarization, atrial repolarization

the QRS complex represents

ventricular repolarization

the T wave represents

AV node delay

the PQ segment represents

ventricular systole

the QT segment represents

ventricular diastole

the QT interval represents

1st degree heart block

this increases PQ segment and delay between atrial and ventricular contraction; slow/diminished conduction through AV node

2nd degree heart block

this loses relationship between P wave and QRS complex; slowed/stopped conduction through AV node

3rd degree heart block

this causes the P wave to become independent of QRS; loss of conduction through AV node

ventricular fibrillation

the loss of coordination of electrical activity of heart

sinus bradychardia

an EKG with less than 50 bpm may indicate

heart block (3rd degree)

an EKG with missing QRS complex may indicate

sinus tachycardia

an EKG with more than 100 bpm may indicate

systole

the period of ventricular contraction is also known as

diastole

the period of ventricular relaxation is also known as

AV valves

what valves open when atrial pressure is greater than ventricular pressure?

semilunar valves

what valves open when ventricular pressure is greater than arterial pressure?

ventricular filling

phases of cardiac cycle:

middle of ventricular diastole, AV valves open, semilunar valves closed, passive filling

isovolumetric ventricular contraction

phases of cardiac cycle:

start of systole, AV and semilunar valves closed, no blood flow

increases

when the ventricle contracts, what happens to its pressure?

ventricular ejection

phases of cardiac cycle:

remainder of systole, semilunar valves open, ventricular pressure then < aortic pressure and semilunar valves close

isovolumetric ventricular relaxation

phases of cardiac cycle:

onset of diastole, AV and semilunar valves closed, no blood flow

low pressure

during diastole, what is the aortic pressure?

high pressure

during systole, what is the aortic pressure?

EDV

volume of blood in ventricle at the end of diastole

ESV

volume of blood in ventricle at the end of systole

SV

volume of blood ejected from ventricle each cycle

SV = EDV - ESV

how do you calculate stroke volume?

EF (ejection fraction)

fraction of end-diastolic volume ejected during a heartbeat

CO = SV x HR

how do you calculate cardiac output?

extrinsic

the neural and hormonal regulation of cardiac output is referred to as

intrinsic

the autoregulation of cardiac output is referred to as

vagus nerve

which cranial nerves innervate the heart?

T1-T4

which spinal nerves innervate the heart?

increases HR

how does more sympathetic activity affect heart rate?

decreases HR

how does more parasympathetic activity affect heart rate?

epinephrine, glucagon

list hormones that may increase heart rate

increases stretch

how does an increase in EDV affect stretch?

afterload (aortic pressure)

the pressure that needs to be overcome during ejection

change P/R

how do you calculate flow?

MAP (mean arterial pressure)

the pressure in the aorta

CVP (central venous pressure)

the pressure in vena cava

greater than

is the pressure gradient in the systemic circuit greater than/less than/equal to pressure gradient in pulmonary circuit?

greater than

is resistance through systemic circuit greater than/less than/equal to resistance through pulmonary circuit?

vessel radius/length, blood viscosity

what factors affect resistance to flow?

increase resistance

a decrease in vessel radius does what to resistance?

decreases flow

an increase in resistance does what to flow?

low

do arteries have low or high compliance?

compliance

measure of how pressure will change with change in volume

largely increase

both large and small increases in blood volume do what to pressure?

systolic bp

the maximum pressure of the aorta is referred to as

diastolic bp

the minimum pressure of the aorta is referred to as

MAP = SP + (2 x DP)/3

how do you calculate MAP?

decreases radius

an increase in vessel contraction does what to the radius?

vasodilation

an increase in metabolic activity causes

CO2, K, H

vasodilation is caused by increased production of these 3 ions

vasoconstriction

a decrease in metabolic activity causes

same rate

in a steady state in metabolic activity, how do the rates of O2 delivery and O2 consumption differ?

same rate

in a steady state in metabolic activity, how do the rates of CO2 production and CO2 removal differ?

consumed faster

with increased metabolic rate, how do the rates of O2 delivery and O2 consumption differ?

produced faster

with increased metabolic rate, how do the rates of CO2 production and CO2 removal differ?

vasodilation

this happens in response to low O2 and high CO2 in vessels

active hyperemia

increased blood flow in response to increase metabolic activity

reactive hyperemia

increased blood flow in response to previous reduction in blood flow

myogenic response

change in vascular resistance in response to stretch of blood vessels

myogenic autoregulation

purpose of this is to keep blood flow constant

increases co

how does exercise affect cardiac output?

muscles and heart

during exercise, where does increase in blood flow occur?

vasoconstriction

norepinephrine causes vasoconstriction or vasodilation?

both (both on a, dilation on b)

epinephrine causes vasoconstriction or vasodilation?

increases

when metarterioles contract, what happens to blood flow

decreases

when precapillary sphincters contract, what happens to blood flow

filtration

movement out of circulation

absorption

movement into circulation

filtration

does capillary hydrostatic pressure favor filtration or reabsorption?

reabsorption

does interstitial hydrostatic pressure favor filtration or reabsorption?

increases pressure

an increase in blood volume does what to the pressure?

short-term regulation

regulation for cardiac output & total peripheral resistance; under neural control

long-term regulation

regulation for blood volume; kidneys involved; under hormonal control

baroreceptors

pressure receptors

baroreceptor reflex

negative feedback loop to maintain blood pressure at normal level

decrease ps activity

what do hemorrhages do to parasympathetic activity?

no only responds

does the baroreceptor correct the problem?

parasympathetic ns

the only factor that decreases MAP is

decrease in volume

what activates baroreceptors?

sympathetic

during inspiration, what nervous system is most active?

parasympathetic

during exhalation of breath, what nervous system is most active?

hematocrit

the percentage of RBC in blood

O2 and CO2 transport

what is the major function of RBC?